In the method known from DE 10 2006 053 193 A, the containers blow molded or stretch blow molded from the preforms are sterilized on the transport path between the blow module and the filling machine. In the process, first a sterilization treatment is performed on the inner surfaces, then a sterilization treatment is performed on the outer surfaces in an external tunnel, and finally sweeping with sterile air is performed. The apparatus and control complexity for the sterilization treatment is high. For example, treatment stars with lifting devices involving complex control system are required, and relative low pressures and temperatures must be employed as the blow molded containers comprise thin walls and large surfaces. The device suited for carrying out the method is large and includes very long transport paths, especially for the containers.
In the method known from EP 1 896 245 A, two sterilization treatments are already performed at the preforms on the transport path to the blow module, that means a first sterilization treatment upstream of the heating device, and another sterilization treatment downstream of the heating device. However, especially in the blow module, so many components come into contact with the preforms and the containers which cannot be brought to a sterile state with reasonable efforts, that the containers are possibly contaminated again during filling. However, this known method considers the fact that a sterilization treatment of the preforms can be carried out relatively aggressively and therefore efficiently in view of the employed pressure and the temperatures as the preforms with a relatively thick wall thickness have smaller surfaces and are brought to a temperature advantageous for the sterilization treatment, and possible residues are largely removed during blow molding or stretch blow molding by exchanging the air volume. Finally, for the medium used in the sterilization treatment, one can choose a higher temperature due to the ruggedness of the preform, increasing the efficiency of the sterilization treatment.
In the method known from WO 2009/052800 A, a first sterilization treatment is performed at the preforms on their transport path to the heating device into the heating device with energy beams generated by generators, and another sterilization treatment is performed at the containers along the transport path of the containers from the blow module to a discharge section of the blow module, again with energy beams of a generator. The preforms can be contaminated again in the heating device, and the containers can be contaminated in the blow molds and on the transport path to the filling machine.
In the method known from EP 0 996 530 A, the preforms and the containers are each subjected to a sterilization treatment. The sterilization treatment of the preforms is already effected upstream of the heating device and into the heating device, or between the heating device and the blow module. The sterilization treatment of the containers is effected as a completion of the blow molding, so that these can be subsequently contaminated again.